(1) Field of the Invention
The present invention relates to a vacuum cleaner, and more particularly, to a vacuum cleaner having means of killing noxious small organisms, such as mites, caught in the dust chamber of the cleaner body.
(2) Description of the Prior Art
Japanese Unexamined Patent Publication No. 127026/1987 discloses a vacuum cleaner in which air heated by an electric air blower in a body of the vacuum cleaner circulates through a dust chamber so that noxious small organisms, such as mites, caught in the dust chamber and are killed by heat. In this prior art embodiment, a delay timer switch or a bimetal switch is used as switching means for stopping mite killing operation. However, such vacuum cleaner has disadvantages as follows: In the vacuum cleaner employing the delay timer switch as the switching means, the mite killing operation is carried out independent of a temperature heating the dust chamber, and the electric air blower never stops until a preset time even when a temperature of the electric air blower itself rises because of a rise in the temperature in the ambient air, for example, in summer. On the other hand, in the vacuum cleaner employing the bimetal switch, the electric air blower never stops to continue the mite killing operation until a temperature in the heated dust chamber reaches a temperature preset at the bimetal switch, if the temperature in the ambient air falls, for example, in winter.